#include<stdio.h>
#include<unistd.h>
#include<sys/types.h>
int main()
{
    printf("begin：我是一个进程，pid:%d，ppid:%d\n",getpid(),getppid());
    sleep(5);
    pid_t id = fork();
    if(id == 0) 
    {
        //子进程
        while(1)
        {
            printf("我是子进程，pid:%d,ppid:%d\n",getpid(),getppid());
            sleep(1);
        }
    }
    else if(id > 0)
    {
        //父进程
        while(1)
        {
            printf("我是父进程，pid:%d,ppid:%d\n",getpid(),getppid());
            sleep(1);
        }
    }
    else 
    {
        //error
         
    }

    //printf("before : only one line\n");
    //fork();
    //printf("after : only one line\n");
    //pid_t id = getpid();
    // while(1)
    //{
    //   printf("I am a process, my id is %d,parent id is %d\n",getpid(),getppid());
    //    sleep(1);
    //}
    return 0;
}
